I have an 18 x 36 inground pool which I think is 36,000 gal. Our Alkalinity is 280 with a PH of 6.2. Over the course of 4 days we have added two gallons of muratic acid to lower the alkalinity because it was originally 320 with a high PH. Now the PH is low and the alkalinity is still high. I am not sure what to do next. Our water is cloudy and the free chlorine is .5 Thanks!

Aerate the water and add more chlorine as well. Aeration drives the carbon dioxide out of the pool and that raises the pH. When the pH gets higher, say to 7.4 or higher, then add acid to lower it back down to 7.2 or 7.0. The procedure for lowering the pH is shown here.